1,923 research outputs found
Plant Growth Promotion and Biocontrol of Pythium ultimum by Saline Tolerant Trichoderma Isolates under Salinity Stress
This present study evaluates three isolates of Trichoderma as plant growth promoting or biological control agents: Trichoderma aggressivum f. sp. europaeum, Trichoderma saturnisporum, and the marine isolate obtained from Posidonia oceanica, Trichoderma longibrachiatum. The purpose is to contribute to an overall reduction in pesticide residues in the fruit and the environment and to a decrease in chemical fertilizers, the excess of which aggravates one of the most serious abiotic stresses, salinity. The tolerance of the different isolates to increasing concentrations of sodium chloride was evaluated in vitro, as well as their antagonistic capacity against Pythium ultimum. The plant growth promoting capacity and effects of Trichoderma strains on the severity of P. ultimum on melon seedlings under saline conditions were also analysed. The results reveal that the three isolates of Trichoderma, regardless of their origin, alleviate the stress produced by salinity, resulting in larger plants with an air-dry weight percentage above 80% in saline stress conditions for T. longibrachiatum, or an increase in root-dry weight close to 50% when T. aggressivum f. sp. europaeum was applied. Likewise, the three isolates showed antagonistic activity against P. ultimum, reducing the incidence of the disease, with the highest response found for T. longibrachiatum. Biological control of P. ultimum by T. aggressivum f. sp. europaeum and T. saturnisporum is reported for the first time, reducing disease severity by 62.96% and 51.85%, respectively. This is the first description of T. aggressivum f. sp. europaeum as a biological control agent and growth promoter. The application of these isolates can be of enormous benefit to horticultural crops, in both seedbeds and greenhouses
k-Coherence of measures with non-classical weights
7 pages, no figures.-- MSC2000 codes: Primary 42C05; Secondary 33C25.MR#: MR1882617 (2003b:42042)The concept of k-coherence of two positive measures μ1 and μ2 is useful in the study of the Sobolev orthogonal polynomials. If μ1 or μ2 are compactly supported on R then any 0-coherent pair or symmetrically 1-coherent
pair (μ1, μ2) must contain a Jacobi measure (up to affine transformation). Here examples of k-coherent pairs (k ≥ 1) when neither μ1 nor μ2 are Jacobi are constructed.Research of F. Marcellán supported by Dirección General de Investigación(Ministerio de Ciencia y Tecnología) of Spain under grant BFM2000-0206-C04-01. Research of A. Martínez-Finkelshtein partially supported by INTAS project 2000-272, a research grant of Dirección General de Enseñanza Superior (DGES) of Spain, project code PB95-1205, and by Junta de Andalucía, Grupo de Investigación FQM 0229. Research of J. J. Moreno-Balcázar partially supported by Junta de Andalucía, Grupo de Investigación FQM 0229, and INTAS project 2000-272.Publicad
Cladobotryum mycophilum as Potential Biocontrol Agent
A study was conducted to explore the efficacy of potential biocontrol agent Cladobotryum mycophilum against different phytopathogenic fungi. The growth rates of 24 isolates of C. mycophilum were determined, and their antagonistic activity was analysed in vitro and in vivo against Botrytis cinerea, Fusarium oxysporum f. sp. radicis-lycopersici, Fusarium oxysporum f.sp. cucumerinum, Fusarium solani, Phytophthora parasitica, Phytophthora capsici, Pythium aphanidermatum and Mycosphaerella melonis. Most isolates grow rapidly, reaching the opposite end of the Petri dish within 72–96 h. Under dual-culture assays, C. mycophilum showed antagonistic activity in vitro against all phytopathogenic fungi tested, with mycelial growth inhibition ranging from 30 to 90% against all the different phytopathogens tested. Similarly, of all the selected isolates, CL60A, CL17A and CL18A significantly (p < 0.05) reduced the disease incidence and severity in the plant assays compared to the controls for the different pathosystems studied. Based on these results, we conclude that C. mycophilum can be considered as a potential biological control agent in agriculture. This is the first study of Cladobotryum mycophilum as a biological control agent for different diseases caused by highly relevant phytopathogens in horticultur
Calidad de vida en adultos mayores y motivos de práctica deportiva
Regular physical activity practice provides benefits and improves quality of life (QOL). The purpose of this study was to know the level of QOL of older adults who practice physical activity. The study was quantitative, descriptive and cross-cutting with accidental sampling, with 554 participants of which 37.2% (n=206) are men and 62.8% (n=348) women, with an average age of around 65 years (M=64.9; DT=10.3). To know the QOL of the sample members, the WHOQOL-BREF questionnaire was used, 26 items and four dimensions, with five-option Likert scale responses (1-5). Regarding statistics, Cronbach alpha, Pearson linear correlation, t-Student, ANOVA, Kolmogorov-Smirnov and Levene test were applied with SPSS 25.0 for Windows. Regarding the results, it should be noted that the environment dimension was the best valued followed closely by the psychological health dimension and the worst valued was social relationships. There were no significant differences in sex. In terms of age, when one gets older, psychological health and the environment decrease, while increasing social relationships. In conclusion, older adults with academic qualifications had better values in psychological health and in the environment.La práctica regular de actividad física aporta beneficios y mejora la calidad de vida (CV). El propósito del estudio fue conocer el nivel de CV de los ancianos que practican actividad física. El estudio fue cuantitativo, descriptivo y transversal con muestreo accidental, con 554 participantes de los cuales el 37,2% (n=206) son hombres y el 62,8% (n=348) mujeres, con una edad media en torno a los 65 años (M=64,9; DT=10,3). Para conocer la CV de los miembros de la muestra se utilizó el cuestionario WHOQOL-BREF, 26 ítems y cuatro dimensiones, con respuestas de escala Likert de cinco opciones (1-5). En cuanto a la estadística, se utilizó alfa de Cronbach, correlación lineal de Pearson, t-Student, ANOVA, Kolmogorov-Smirnov y test de Levene, con el programa SPSS 25.0 para Windows. En cuanto a los resultados, cabe señalar que la dimensión medioambiental fue la mejor valorada seguida de cerca por la dimensión salud psicológica y la peor valorada fueron las relaciones sociales. No existen diferencias significativas en cuanto al sexo. En cuanto a la edad, cuando se envejece, la salud psicológica y el medio ambiente disminuyen, al tiempo que aumentan las relaciones sociales. En conclusión, los adultos mayores con titulación académica tuvieron mejores valores en salud psicológica y en el medio ambiente
Humoral response (IgG) of goats experimentally infected with Fasciola hepatica against cysteine proteinases of adult fluke
The use of cysteine proteinases from Fasciola hepatica adult flukes for the
serodiagnosis of caprine fasciolosis by means of an indirect ELISA test was studied. Two
proteolytic fractions from adult fluke homogenates, with apparent molecular weights of 28 and
34 kDa (P28 and P34 respectively), were characterised as cysteine proteinases using azocasein
assays and gelatin gel analysis. Both P28 and P34 fractions were electroluted and used as antigens
in two different indirect ELISA tests. Serum IgG levels against P28 and P34 in goats given an
experimental primary infection with 200 metacercariae or in goats given two experimental
infections with 200 metacercariae were determined and compared with those observed in an
uninfected control group. ELISA tests using both cysteine proteases showed a rapid and consistent
detection of specific IgG in all experimentally infected goats. The IgG response to P28 was the first
to be detected as early as 2–3 weeks post-infection and remained elevated throughout the
experiment. The response to P34 was detected later (4–6 wpi) and disappeared in some animals at
18 wpi, while flukes were still present in the bile ducts. No significant differences were observed
between the anti-P28 and anti-P34 IgG responses between animals receiving a primary or a
challenge infection. The results of our study, although preliminary, are promising since the P28
ELISA described here may be a reliable method for the immunodiagnosis of F. hepatica infection
in goats
Desarrollo de una herramienta de ayuda a la enseñanza de heurísticas
En el presente trabajo se presenta una aplicación desarrollada en entornos gráficos interactivos que permite simular, paso a paso, el desarrollo de heurísticas. Esta herramienta facilita la docencia al profesor de la asignatura optativa Heurísticas que se imparte en la Ingeniería Técnica en Informática de Gestión de la Universidad de La Laguna y permite al alumno comprender y asimilar conceptos, y mejorar el conocimiento práctico de estas técnicas
Características y comportamiento de los recursos humanos como potenciadores de la innovación empresarial
Actualmente, la necesidad de adaptarse a los continuos cambios que se suceden en el entorno, ha convertido a la innovación en una actividad empresarial determinante para la obtención de ventajas competitivas. Las empresas son conscientes de la necesidad de innovar, no obstante, muchas de ellas encuentran grandes barreras al desarrollo de este tipo de actividades.
El presente trabajo expone los fundamentos teóricos que explican la importancia del factor humano en el proceso de generación e implantación de innovaciones en la empresa. Por otro lado, contrasta empíricamente la incidencia de dicho factor mediante el análisis de una muestra de empresas industriales españolas
Diesel engine optimization and exhaust thermal management by means of variable valve train strategies
[EN] Due to the need to achieve a fast warm-up of the after-treatment system in order to fulfill the pollutant emission regulations, a growing interest has arisen to adopt variable valve timing technology for automotive engines. Several variable valve timing strategies can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to carry out a simulation study comparing several exhaust variable valve actuation strategies. A steady-state analysis has been done in order to evaluate the potential of the different strategies at different operating points. Finally, the effect on the after-treatment warm-up, fuel economy and pollutant emission levels was evaluated over the worldwide harmonized light vehicles test cycle. As a conclusion, the combination of an advanced exhaust (early exhaust valve opening and early exhaust valve closing) and a delayed intake (late intake valve opening and late intake valve closing) presented the best trade-off between exhaust temperature increment and fuel consumption, which achieved a mean temperature increment during low-speed phase of the worldwide harmonized light vehicles test cycle of 27¿°C with a fuel penalty of 6%. The exhaust valve re-opening technique offers a worse trade-off. However, the exhaust valve re-opening leads to lower nitrogen oxide (29% less) and carbon monoxide (11% less) pollutant emissions.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research has been partially funded by the European Union's Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 ("DiePeR") and by the Spanish government under the grant agreement TRA2017-89894-R. The authors want to acknowledge the "Apoyo para la investigacion y Desarrollo (PAID)," grant for doctoral studies (FPI S2 2018 1048), of Universitat Politecnica de Valencia.Arnau Martínez, FJ.; Martín, J.; Pla Moreno, B.; Auñón-García, Á. (2021). Diesel engine optimization and exhaust thermal management by means of variable valve train strategies. International Journal of Engine Research. 22(4):1196-1213. https://doi.org/10.1177/1468087419894804S1196121322
Use of PV plants monitoring to characterize PV arrays power
PV plants require a monitorization of their electrical parameters to achieve its best performance. Lately, it is more and more common that SCADA systems monitor currents and voltages even of every single string. These measurements which use to be stored instantaneously with a frequency like the one established on inverters and energy meters (usually each 10, 15, 20 or 60 minutes) are useful to detect faults. Unfortunately, it is not taken advantage of them to characterize the PV arrays. A better option would be to exploit this monitoring capability not only to detect operation failures, but also to characterize the PV strings/arrays. In order to implement this characterization it is needed to use the adequate devices to measure voltages and currents and determine which should be the optimal frequency to store data, depending on they are instantaneous or mean values. This paper presents the results of the DC monitoring of a grid-connected PV array of 5.8 kWp, installed on the headquarters of the Instituto de Energía Solar of the Universidad Politécnica de Madrid (IES-UPM), located in the Campus Sur of Vallecas (Madrid), which allows characterizing the PV arrays power. To study the relation between sampling frequency and its impact in the accuracy of the power averages each 1’, 5’, 10, and 15’ have been calculated from instantaneous measurements, and they have been analysed to evaluate which is the more adequate sampling rate for instantaneous and mean values
Evaluation of the competitiveness of agri-food sector in the región of the Alcarria Conquense(Spain)
The agrifood industry, like other sectors, faces the ongoing challenge of improving their competitiveness in order to strengthen its market presence and cater to the growing global population. This research measures the competitiveness of the agrifood industry in the region of La Alcarria Conquense (Spain), in the framework of the evaluation of programs in the territory that have aimed at improving and enhancing this sector. Through building the competitiveness profiles (Porter, 1990) and cluster analysis we have identified six competitive strategy patterns in food companies in the region. In addition, we have analyzed each of the areas of competitiveness and we can identify the strengths and weaknesses of the sector, and identify recommendations for increasing the responsiveness of the territory. Among the defining characteristics are the lack of association, the limitation on payment systems or virtual absence of training and innovation. However, programs to support the sector are highly valued and reverse in the long-term viability of these companies
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